Oxygen chamber used to reduce damage following heart attack

November 17, 1992|By Los Angeles Times

Dr. George Hart is a retired Navy physician who makes his living operating on people's hearts and lungs. Twelve years ago, as he lay in an emergency room after suffering a heart attack while driving to work, the cardiovascular surgeon took his treatment into his own hands.

He ordered his nurse to put him in a hyperbaric oxygen chamber -- the kind used to treat deep sea divers who suffer from decompression illness, known as "the bends." Within 30 minutes, Dr. Hart said, the intense pain in his chest was gone.

That experience in September 1980, in Long Beach, Calif., led Dr. Hart on a quest to determine if emergency treatment in pressurized hyperbaric chambers is beneficial to heart attack patients. Yesterday, at an annual scientific conference hosted by the American Heart Association in New Orleans, he and his colleagues were scheduled to report that their preliminary studies show that the treatment works.

In a study of 49 patients who had just suffered heart attacks, physicians at Long Beach Memorial Medical Center found that use of hyperbaric chambers, when combined with clot-dissolving drugs, relieved chest pain and significantly reduced damage to the heart muscle contrasted with administering the drugs alone.

In some heart attacks, blood clots close off the coronary artery, cutting off oxygen to the heart and causing the muscle to scar.

Decades ago, doctors theorized that hyperbaric oxygen chambers, in which patients are provided with pure oxygen, might help prevent this scarring.

Studies in this area were abandoned with the introduction of clot-dissolving drugs in the 1970s. Yet, according to Dr. Myrvin Ellestad, who directed the Long Beach Memorial research, the drugs can take two hours to dissolve the clots, during which time the heart usually sustains damage because of continued oxygen deficiency.

In the hyperbaric chamber, Dr. Ellestad said, patients receive oxygen at twice the normal atmospheric pressure, which increases the blood's oxygen level by about 15 times.